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1. Field of the Invention
The invention relates to communication networks, and specifically, to a method and system for providing call tones in communication networks.
2. Description of the Prior Art
Call tones are generated in communication networks to provide callers with feedback regarding the status of calls and call connections. Examples of specific call tones include a dial tone, a ringback tone, a busy signal tone, and a reorder tone. The reorder tone is sometimes referred to as a fast busy signal in the art. Typically, call tones are provided in communication networks by a terminating communication device upon completion of the call connection. In some applications however, call tones can be provided by an originating communication device by triggering the call tone generation using a control or signaling channel.
FIG. 1 illustrates an example of call tone control and generation for a call session in the PSTN. On FIG. 1 the calling party removes the receiver from the calling party""s telephone 100. The originating switch 101 detects the off-hook and provides a dial tone to the calling party""s telephone 100. Responsive to receiving the dial tone, the user enters the digits for a call destination. The originating switch 101 processes the entered digits and provides a call setup message to the network 102. The network 102 provides the call setup message to the terminating switch 103 and reserves a connection between the originating switch 101 and the terminating switch 103. In response to receiving the call setup message, the terminating switch 103 provides an acknowledgment message to the network 102. If the terminating switch 103 detects the called party""s telephone 104 is off-hook or busy, the terminating switch 103 provides busy signal tones over the network 102 to the calling party""s telephone 100. If the terminating switch 103 does not detect that the called party""s telephone 104 is off-hook or busy, the terminating switch 103 provides ringback tones over the network 102 to the calling party""s telephone 100. The terminating switch 103 also rings the called party""s telephone 104 to announce the incoming call.
FIG. 2 illustrates another example of call tone generation and control for a call session in a packet communication network. On FIG. 2 the calling party removes the receiver from the calling party""s telephone 200. The originating communication hub 201 detects the off-hook event and provides an off-hook message to the network 202. Responsive to receiving the off-hook message, the network 202 provides a dial tone to the calling party""s telephone 200 via the originating communication hub 201. Responsive to receiving the dial tone the user enters the digits for the call destination. The originating communication hub 201 detects the digits and provides the digits to the network 202. The network 202 processes the digits and generates a setup message for a terminating communication hub 203 connected to the called party""s telephone 204. Responsive to receiving the setup message, the terminating communication hub 203 provides a setup acknowledgment message to the network 202. If the called party""s telephone 204 is off-hook or busy, the terminating communication hub 203 provides busy signal tones over the network 202 and communication hub 201 to the calling party""s telephone 200. If the terminating communication hub 203 does not detect the called party""s telephone 203 is off-hook or busy, the terminating communication hub 203 provides ringback tones over the network 202 and communication hub 201 to the calling party""s telephone 200. The terminating communication hub 203 also rings the called party""s telephone 204 to announce the incoming call.
It is a problem in packet communication networks to provide call tones over the network from the terminating device. The communication path between the communication hub and the network includes a limited bandwidth capacity. Unfortunately, effective call tone generation is not supported because new services such as call waiting, call forwarding, and three-way-calling have increased network bandwidth demands. Therefore, a need exists in the art to free bandwidth currently utilized by call tone generation and control in packet communication networks.
The present invention advances the art by providing a communication hub that provides call tones in communication networks at points proximate the calling device. Advantageously, bandwidth required for call completion in the communication network is significantly reduced because call tones are provided proximate the calling device using in-band call tone messaging. Also advantageously, the in-band call tone messaging could also serve as a validation that the bearer channel is functioning properly before call completion. Thus, service assurance is provided before call completion and early detection of network failures is realized. Some examples of call tones that could be provided include without limitation, ringback tones, busy signal tones, and reorder tones.
The communication hub is comprised of an interface coupled to a processor and a tone generator. The tone generator is configured to generate the call tones under control of the processor. The processor is configured to process an in-band call tone request message to direct the tone generator to provide the call tones to a call device. The interface is configured to receive the call tone request message and transmit the call tones to the call device.
In the context of the present invention the first, second, third, fourth, etc. connotations used to reference the messages, the calls, and the devices are used for the purpose of differentiating between different messages, different calls, and different devices and are not used to indicate a message sequence, call sequence or processing sequence. Also in the context of the present invention, an on-network call session is defined as a call session between two devices connected to the same communication network. An off-network to on-network call session and an on-network to off-network call session are defined as an incoming call session or an outgoing call session, respectively, between two devices connected to different communication networks. For example, an incoming call session or an outgoing call session between a call device connected to a packet network and a call device connected to the PSTN. In-band is defined as using the bearer portion of a communication path, for example, over the bearer channel in an asynchronous transfer mode (ATM) connection. Those skilled in the art will appreciate that in some environments, such as an Internet Protocol (IP) environment, in-band could simply be a pair of addresses, such as the address of the originating device and the address of the terminating device.